Nerve blocks with 5% butamben suspension for the treatment of chronic pain syndromes

Abstract

Background and Objectives. Butamben is a non-water-soluble local anesthetic that can be prepared as an aqueous suspension for nerve blocks. This report describes the use of 5% butamben suspension for the treatment of chronic pain of cancer and noncancer origin. Methods. The clinical courses of 75 consecutive patients were analyzed following 5% butamben nerve blocks (35 epidural blocks only, 33 peripheral nerve blocks only, and 7 had both epidural and peripheral nerve blocks). Epidural blocks were performed as a series of four with additional blocks offered if needed. Peripheral nerve blocks were done as a single block with repeat injections if needed. Injection volumes varied between 15 and 25 mL for epidural injections and 5 and 20 mL for peripheral nerve blocks. Successful therapy was defined as a ≥75% reduction in subjective pain assessments for ≥4 weeks or until death. Daily opioid requirements were also recorded. Results. Fifty-four of the 75 patients (72%) were successfully treated. This included 48 of 67 cancer patients (71.6%) and 6 of 8 noncancer patients (75%). Median duration of pain relief was 12 weeks (range, 1–96) in the cancer patients and 10 weeks (range, 6–166) in the noncancer patients. Mean reduction in opioid requirements in successfully treated cancer patients was 74 ± 5%. Pain on epidural injection occurred in half of the patients and was the most prevalent complication of treatment. Five patients had signs of intravascular injection. There were no serious long-term sequelae. Conclusions. When used as described in this report, 5% butamben suspension appears to be effective for treatment of chronic pain of both cancer and noncancer origin and has a low incidence of adverse sequelae.